using System;
using iTextSharp.text.error_messages;
/*
 * $Id: RomanAlphabetFactory.cs 106 2009-12-07 12:23:50Z psoares33 $
 * 
 *
 * This file is part of the iText project.
 * Copyright (c) 1998-2009 1T3XT BVBA
 * Authors: Bruno Lowagie, Paulo Soares, et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY 1T3XT,
 * 1T3XT DISCLAIMS THE WARRANTY OF NON INFRINGEMENT OF THIRD PARTY RIGHTS.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Affero General Public License for more details.
 * You should have received a copy of the GNU Affero General Public License
 * along with this program; if not, see http://www.gnu.org/licenses or write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA, 02110-1301 USA, or download the license from the following URL:
 * http://itextpdf.com/terms-of-use/
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public License,
 * you must retain the producer line in every PDF that is created or manipulated
 * using iText.
 *
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the iText software without
 * disclosing the source code of your own applications.
 * These activities include: offering paid services to customers as an ASP,
 * serving PDFs on the fly in a web application, shipping iText with a closed
 * source product.
 *
 * For more information, please contact iText Software Corp. at this
 * address: sales@itextpdf.com
 */

namespace iTextSharp.text.factories {

    /**
    * This class can produce String combinations representing a number.
    * "a" to "z" represent 1 to 26, "AA" represents 27, "AB" represents 28,
    * and so on; "ZZ" is followed by "AAA".
    */
    public class RomanAlphabetFactory {

        /**
        * Translates a positive integer (not equal to zero)
        * into a String using the letters 'a' to 'z';
        * 1 = a, 2 = b, ..., 26 = z, 27 = aa, 28 = ab,...
        */
        public static String GetString(int index) {
            if (index < 1) throw new FormatException(MessageLocalization.GetComposedMessage("you.can.t.translate.a.negative.number.into.an.alphabetical.value"));
            
            index--;
            int bytes = 1;
            int start = 0;
            int symbols = 26;  
            while (index >= symbols + start) {
                bytes++;
                start += symbols;
                symbols *= 26;
            }
                  
            int c = index - start;
            char[] value = new char[bytes];
            while (bytes > 0) {
                value[--bytes] = (char)( 'a' + (c % 26));
                c /= 26;
            }
            
            return new String(value);
        }
        
        /**
        * Translates a positive integer (not equal to zero)
        * into a String using the letters 'a' to 'z';
        * 1 = a, 2 = b, ..., 26 = z, 27 = aa, 28 = ab,...
        */
        public static String GetLowerCaseString(int index) {
            return GetString(index);        
        }
        
        /**
        * Translates a positive integer (not equal to zero)
        * into a String using the letters 'A' to 'Z';
        * 1 = A, 2 = B, ..., 26 = Z, 27 = AA, 28 = AB,...
        */
        public static String GetUpperCaseString(int index) {
            return GetString(index).ToUpper(System.Globalization.CultureInfo.InvariantCulture);
        }

        
        /**
        * Translates a positive integer (not equal to zero)
        * into a String using the letters 'a' to 'z'
        * (a = 1, b = 2, ..., z = 26, aa = 27, ab = 28,...).
        */
        public static String GetString(int index, bool lowercase) {
            if (lowercase) {
                return GetLowerCaseString(index);
            }
            else {
                return GetUpperCaseString(index);
            }
        }
    }
}
